SLVK312 July   2026 DAC39RF10-SEP

 

  1.   1
  2.   2
  3.   Trademarks
  4. 1Introduction
  5. 2Single-Event Effects
  6. 3Device and Test Board Information
  7. 4Irradiation Facility and Setup
  8. 5Test Setup and Procedures
  9. 6Single-Event Latch-Up (SEL) Results
  10. 7Single-Event Functional Interrupt (SEFI) Results
    1. 7.1 Converter Performance and Digital (DUC + JESD204C Link) Tolerance
    2. 7.2 Configuration Register Hardness
    3. 7.3 SPI Programming During Irradiation
  11. 8SEU Results
    1. 8.1 JESD204C Link Monitoring Results
    2. 8.2 Digital Up-Converter and NCO Upset Recovery
    3. 8.3 Estimating Upset Rates in Unprotected Data Paths
    4. 8.4 Event Rate Calculations
    5. 8.5 Summary of Radiation Tolerance
  12. 9References
  13.   A Appendix: Recommendations for Hi-Rel Systems
    1.     A.1 Summary of Rad-Hard Design Features
    2.     A.2 SPI Programming
    3.     A.3 JESD204C Reliability
    4.     A.4 Equalizer Usage in Radiation Environments
    5.     A.5 NCO Reliability
    6.     A.6 NCO Frequency and Phase Correction (Strategy #1)
    7.     A.7 NCO Frequency Correction (Strategy #2)
    8.     A.8 NCO Self-Sync/Self-Coherent Mode (Strategy #3)

A.3 JESD204C Reliability

The JESD204C receiver is implemented with high-speed flip-flops that are not single-upset-immune. As a result, the JESD204C link can experience various errors when exposed to radiation.

To improve the overall reliability of the link and verify the link can automatically recover from an upset, several recommendations must be followed.

  1. Use subclass 1 operation by setting SUBCLASS = 1.
  2. 64b/66b link encoding (JENC = 1) is preferred over 8b/10b encoding. The 64b/66b link layer provides full-time block and EMB synchronization (pilot) signals, so misalignment caused by radiation can be detected quickly and consistently. In contrast, the 8b/10b link layer relies on synchronization characters that do not have a high occurrence rate, so misalignment takes longer to detect.
  3. Use a periodic and continuous SYSREF signal. Keep SYSREF alignment enabled at all times in the Tx and Rx devices. If radiation upsets the Tx or Rx LMFC/LEMC, the SYSREF signal will re-establish its phase and keep the Rx and Tx synchronized. If this recommendation is not followed, radiation can cause a persistent change in the link latency, or cause lanes to be persistently misaligned (causing persistent, corrupt samples to be sent to the DAC).
  4. The adaptive equalizer loop in the PHY is not implemented for a radiation environment. Static equalization is recommended. See Equalizer Usage in Radiation Environments below.
  5. The Tx logic device that provides data to the Rx must be designed with radiation tolerance in mind. Recommendations include:
    1. When possible, align counters continuously to SYSREF.
    2. FIFOs must have a means to detect and recover automatically from upsets that can cause overflow or underflow conditions.
  6. At this time, there is no known radiation-induced condition that causes the receiver to experience a functional interrupt (link goes down and remains down). However, the user can program JTT to get an additional level of protection from functional interrupts.